Carbon Neutral Hi’ilani Ecohouse gives something back to nature

US architectural firm Studio RMA recently completed the Hi’ilani EcoHouse: a two-family, low-energy property located on an attractive plot on Hawaii's Big Island. The building draws much of its required energy from renewable sources, and Studio RMA strove to offset the CO2 produced during construction by planting extensive forestry.

Though the design of Hi’ilani EcoHouse kept the environment firmly in mind, the comfort of its occupants hasn't been overlooked either. It includes four bedrooms, five bathrooms, a spa facility, two kitchens, wine cellar, 150-seat amphitheater, a 240 sq ft (22 sq m) indoor music stage, and even a recording studio.

Hi’ilani EcoHouse is currently connected to mains electricity, but the plan is for it to eventually go fully off-grid. Until then, a significant quantity of its energy requirements are met by a rainwater-collection system, solar power, and carefully designed passive cooling.

Rainwater runs from the roof of Hi’ilani EcoHouse into a 26,000 US gallon (98,500 liter) tank situated some way down the hill below, before being fed, via solar-powered pumps, into the home or otherwise used as irrigation – either way, nothing is wasted. The water is also filtered before being used for drinking, and can be heated with solar-powered heaters if necessary.

A rooftop weather station, linked to a computer, controls a series of slats on the exterior of the property, opening and closing them so as to channel the prevailing winds, and thus offer natural ventilation.

Dual rooftop-based solar arrays are tasked with providing electricity. A larger 9.33 KW array provides 220-volt AC for general use (and powers all appliances), while a smaller .66 KW unit offers 24-volt DC for the aforementioned motorized ventilation slats. LED lighting is also installed throughout the property.

However, no matter how modest Hi’ilani EcoHouse's non-renewable energy requirements, its construction necessitated the production of large quantities of CO2 – a point often overlooked in the construction of so-called "green" homes.

Therefore, as Studio RMA's Robert Mechielsen explains further in the video below, the company sought to mitigate CO2 production with a reforestation initiative which will transform 3 acres (1.2 hectares) of grass into forest and underbrush, thus converting large quantities of CO2 into oxygen and wood over time.

Hi’ilani EcoHouse was completed earlier this month, and is expected to receive eventual LEED Platinum certification on account of its green design.

Adam scours the globe from his home in North Wales in order to bring the best of innovative architecture and sustainable design to the pages of Gizmag. Most of his spare time is spent dabbling in music, tinkering with old Macintosh computers and trying to keep his even older VW bus on the road.

For removing C02 from the atmosphere land-filling grass clippings is faster do to the differing growth rates. I do not recommend this because I would prefer to see the grass clippings go to bio-methane production.

Given the rare earth elements and toxic chemicals used in the production photovoltaic systems. (Both collectors and batteries) I would use solar-thermal collection driving an Ammonia Absorption Engine driven electrical generation and harvest the thermal differential excess to the cooling needs (Kitchen [refrigerators are big electrical consumers] and air conditioning) the AAE has built in energy storage and can use bio-methane (derived from black water, non-woody yard waste, and kitchen scraps) to provide extra power for when the collected solar energy is spent.